Hydraulic systems

ABSTRACT

A hydraulic system including two or more hydraulic components separately operable by means of predetermined mutually arbitrary quantities of pressure medium supplied from a common source of the latter via a common feed conduit through respective individually regulatable quantity control valves. Each quantity control valve incorporates a throttle arrangement and a control slide which are adapted to supply a maximum quantity of pressure medium to their hydraulic component by balancing the pressure on the control slide in opposite axial directions. The control slide in a first axial direction is under a pressure load in front of the throttle arrangement and in an opposite axial direction under a pressure load behind the throttle arrangement plus the pressure exerted by a pressure spring. The control slide is provided with a throttle flange cooperable with a flow opening in a slide guide whereby the supply of pressure medium to the region in front of the throttle arrangement is regulated depending upon the balance position of the control slide with increasing throttling by excess pressure in the first axial direction. Furthermore, the pressure medium of the system is employed as a remote control medium by effecting a controlled &#39;&#39;&#39;&#39;tapping off&#39;&#39;&#39;&#39; of pressure medium from the quantity control valve via a remote control valve and an associated single conduit connection to a remotely disposed pressure discharge source. The balance position of the control slide is thus regulated and the supply of pressure medium to the hydraulic component is controlled according to need.

United States Patent 191 Tveit [111 3,800,831 [4 1 Apr. 2, 1974 HYDRAULIC SYSTEMS [75] Inventor:

[73] Assignee: Patents and Developments A/S,

l-lelldale, Norway [22} Filed: Feb. 22, 1972 [211 App]. No.: 227,858

Oyvind Tveit, Nesttun, Norway [30] Foreign Application Priority Data [58] Field of Search 137/625.48, 625.49, 625.5, 137/612.l, 501

[56] References Cited UNITED STATES PATENTS 2,255,787 9/1941 Kendrick 137/501 X 3,344,805 10/1967 Wapner 137/501 X 1,877,576 9/1932 OConnor... 137/501 X 3,420,265 I/I969 De Paum.... 137/501 1,923,595 8/1933 Temple 137/501 1,934,713 11/1933 Hughes 137/501 X 2,397,299 3/1946 Strid 60/97 P 2,155,421 4/1939 Kenyon et al.. 60/52 R 2,415,603 2/1947 Muller et al. 137/501 X 3,524,386 8/1970 Cudnohufskyu 137/501 X 3,547,158 12/1970 Schelin 137/625.48

FOREIGN PATENTS OR APPLICATIONS 875,766 8/1961 Great Britain 60/426 need.

57 5 ABSTRACT A hydraulic system including two or more hydraulic components separately operable by means of predetermined mutually arbitrary quantities of pressure medium supplied from a common source of the latter via a common feed conduit through respective individually regulatable quantity control valves. Each quantity control valve incorporates a throttle arrangement and a control slide which are adapted to supply a maximum quantity of pressure medium to their hydraulic component by balancing the pressure on the control slide in opposite axial directions. The control slide in a first axial direction is under a pressure load in front of the throttle arrangement and in an opposite axial direction under a pressure load behind the throttle arrangement plus the pressure exerted by a pressure spring. The control slide is provided with a throttle flange cooperable with a flow opening in a slide guide whereby the supply of pressure medium to the region in front of the throttle arrangement is regulated depending upon the balance position of the control slide with increasing throttling by excess pressure in the first axial direction. Furthermore, the pressure medium of the system is employed as a remote control medium by effecting a controlled tapping off of pressure medium from the quantity control valve via a remote control valve and an associated single conduit connection to a remotely disposed pressure discharge source. The balance position of the control slide is thus regulated and the supply of pressure medium to the hydraulic component is controlled according to 11 l s. 3 Drezvi t fi s PATENTEDAPR 21974 3300. 31

SHEEI 2 [IF 3 Y 1 HYDRAULIC SYSTEMS This invention relates to a hydraulic system including two or more hydraulic components, which can be operated separately withpredetermined, mutually arbitrary quantities of pressure medium from a common source of pressure medium via a common feed conduit through their respective individually regulatable quantity control valves, which with the aid of a throttle arrangement and a control slide are adapted to establish the individual, maximum quantity of pressure medium source to the associated hydraulic component by balancing the pressure in opposite axial directions on the control slide, the control slide being in a first axial direction under a pressure load of the pressure in front of the throttle arrangement and in an opposite, second axial direction under a pressure load of the pressure behind the throttle arrangement together with the pres-' sure of a pressure spring, and the control slide being provided with a throttle flange which cooperates with a flow opening ina slide control for regulating the supply of the quantity of pressure medium tothe region in front of the throttle arrangement depending on the control slides balance position with increasing throttling by the excess pressure in the first axial direction.

' The present invention can find application in relatively simple installations, having for example two different hydrauliccomponents, but finds the greater application or can give the greater advantages the more hydraulic components there are in the system. The invention is particularly designed for use on board ship, but is also utilisable, for example, for stationary installations on land.

' There can be included, in one and the same hydraulic system, a large number of hydraulic-components which can be operated at different times and under different operating pressures, from a common source of pressure medium. If desired, there can be connected to the systcm hydraulic components of varying types.

On board a tanker, there can be connected, for example, a series of discharge pumps (one or more for each tank) which are operated separately from the hydraulic system and, in addition, there can be connected freshwater pumps, means for the ships propulsion or control, drive means for various winches etc.

The object of the present invention is to provide a system whereby the various hydraulic components can be operated at the same time, individually in an intended manner by remote control with a relatively simple arrangement of feed conduits and with relatively simple regulating means.

With known systems in which the various hydraulic components are connected to a common source of pressure medium and in which there is to be effected at the same time remote control of the hydraulic components with specific maximum quantities of pressure medium, one has been reduced to employing a separate feed conduit from the central remote control forward to each individual hydraulic component. For a system v Attempts have been made to simplify such known systems by employing a single common ring conduit for a large number of hydraulic components. -Withsttch simplified systems the large number of feed conduits has been avoided, without thereby substantially increasing the pipe cross-section for the one common ring conduit. On the other hand, in view of the high costs and the general complications which known remote control arrangements involve, it has been necessary to abandon a desired remote control and to be reduced to employing relatively complicated, manually regulatable quantity control valves.

With the present invention the particular aim is the achieving of remote control of hydraulic components from a common ring conduit. The aim is to employ a relatively simply constructed quantity control valve known per se for establishing the individual, maximum quantity of pressure medium for the associated hydraulic component and by means of simple means in addition to be able to remotely control such a valve so that the pressure of the medium can be regulated down to the hydraulic component, free of steps in the region between maximum, medium passage, and full-stop.

The hydraulic system according to the invention is characterized in that the control slide in the said second axial direction is under the pressure load of the pressure of the pressure spring and the pressure behind having, for example, 40 hydraulic components, one has 7 the throttle arrangement via a remotely controlled pressure control chamber which via a single conduit connection is connected via a remote control valve to a remotely disposed pressure discharge source for separately regulating the balance position of the control slide and thereby regulating the actual quantity of pressure medium to the hydraulic component according to need.

A particular advantage of the system according-to the invention is that one can employ the systems pressure medium as the remote control medium by quite simply effecting a controlled "tapping off of pressure medium from the quantity control valve via the remote control valve and the associated single conduit connection to the remotely disposed pressure discharge source- Such a simple remote control can be achieved during the use of quantity control valve known per se by quite simply providing the quantity control valve with a coupling for the said conduit connection to the slide valves one pressure chamber in the form of the said pressure control chamber. On completely closing the remote control valve, the quantity control valve can operate as usual for limiting the quantity of pressure medium for the hydraulic component to the desired maximum quantity of pressure medium. On opening the remote control valve, there can be effected a separate control of the pressure in the pressure control chamber and thereby as required regulation of the quantity of pressure medium to the hydraulic component free of steps in the interval between said pressure medium quantity and full stop.

In order that the invention can be more clearly un-' derstood, convenient embodiments thereof will now be described, by way of example, with reference to the accompanying drawings wherein:

FIG. 3 is a section corresponding to FIG. 2 illustrating an alternative form of quantity control valve. In FIG. 1, there are illustrated two drive motors 10, 11 which via their respective shaft couplings 12, 13 drive their respective hydraulic pumps 14, 15. The pumps are connected to an oil tank 16 via a common conduit connection 17 and branch conduits 17a and 17b to the intake sides of the pumps. On the discharge sides of the pumps, the pumps are connected, via their respective branch conduits 18a and 18b, to a common circulation conduit to the tank 16. In the branch conduits 18a and 181), there are coupled safety valves 19a and 19b respectively. On 'the discharge sides, the pumps are further connected, via branch conduits 20a and 20b, to a common feed conduit 20 which passes to a series of hydraulic devices 210, 22a; 21b, 22b; 21c, 22c; 21d, 22d via parallel extending branch conduits 23a, 23b, 23c, 23d. From the hydraulic devices, there extend separate branch conduits 23e, 23f, 23g, 23h to a common return conduit 23, which is connected to the tank 16. In the branch conduits 20a and 20b, there are installed check valves, 24a, 24b. Each hydraulic device comprises a quantity control valve 21 and a hydraulic component 22 regulatably operated by the latter. The valves 21a, 21b, 21c, 21d are connected to their respective hydraulic components 22a, 22b, 22c, 22d by means of connection conduits 23i, 23j, 23k, 231.

At 25, there is shown a remote control stations control panel which is connected to the tank 16 via a return conduit 26. The control panel 25 is provided with control valves 27 and 28 which are connected to a control slide in their respective safety valves 19a and 19b via their respective conduit connections 27a and 28a. The pressure in the conduit connections 27a and 28a can be read off by way of associated manometers 30 and 31 respectively. On the control panel 25 there is further shown a series of control valves 3235 with their respective associated conduits 36-39 to their respective quantity control valves 21a, 21b, 21c and 21d. On the control panel 25 there can be arranged (not shown in FIG. 1) an associated manometer installed in the respective conduits 36-39. Such a manometer is shown at 40 in FIGS. 2 and 3 for the one conduit 36 of the valve 210.

In FIG. 2, there is shown a quantity control valve 21a. There is shown a feed branch conduit 23a and a connection conduit 23i to the hydraulic component (not shown further in FIG. 2), which are connected to ducts 41 and 42 in a cylindrical housing portion 43. The housing portion 43 is closed at opposite ends by end covers 44 and 45. In a first bore 46, there is received a guide-forming insert portion 47 which is fixed between the end cover 44 and a shoulder portion 48 in the housing portion. The insert portion 47 is provided, at the one end, with a first annular groove 49 which communicates with the feed duct 41 while, at the opposite end, it is provided with a second annular groove 50 which communicates with the discharge duct 42. The annular grooves 49 and 50 are connected separately via their respective cross bores 51 and 52 with a common central bore 53 in the insert portion. In the central bore of the insert portion, there is inserted a slide 54 having a stem portion 55 which at opposite ends is provided with flanges 56 and 57 which cooperate with their respective sets of port openings in the associated cross bores 51 and 52. In the stern portion 55, there is formed a narrow bore 58 transversely through the step portion and, from this bore, a second narrow bore 59 axially through the slide to a chamber 60 between the end cover 44 and the flange 56. At the oppositely directed end of the flange 57, there is formed a broad flange 61 which is displaceably received in a second bore 62 in the housing portion 43. Between the cover 45 and the flange 61, there is formed a chamber 63 in which there is received a pressure spring 64 which normally presses the flange 61 against the adjacent end of the insert portion 47. An axial bore 65 extends from the cross bore 52 to a chamber between the flange 61 and the insert portions 47 adjacent end, while a second narrow bore 66 extends from the chamber 63 to the discharge duct 42 to a region just behind a throttle arrangement 67. The throttle arrangement is shown in the drawing formed as a constricted portion of the duct 42, but is able to consist in a manner known per se of a discshaped insert portion having precisely located throughpassages or, if desired, a rotatable disc with the through passage eccentrically arranged relative to the duct.

The described quantity control valve 21 known per se operates in the following manner:

In the position shown in FIG. 2, where the valve 21a is shown in the fully open position, the pressure medium passes from the feed conduit 23a via the duct 41, annular groove 49, cross bores 51, past a throttle passage between the flange 56 and the cross bores 51 to a slide chamber 53a in the central bore 53 and further via the cross bore 52, the annular chamber 46, the permanently located throttle arrangement 67 and the duct 42 to the branch conduit 23i to the hydraulic compo nent.

The throttle arrangement 67 operates so that one gets a certain fall in pressure A p from the region in front of the throttle arrangement to the region behind the throttle arrangement.

In the fully open position shown for the valve 21a to the branch conduit 23i, the quantity of pressure medium supplied is so small (or so much less than the maximum adjusted quantity of pressure medium) that the fall in pressure A p over the throttle arrangement 67 is less than the spring pressure. The pressure in front of the throttle arrangement is transferred via the bores 58, 59 to the upper side of the flange 56 and via the bore 65 to the upper side of the flange 61, while the pressure after the throttle arrangement is transferred via the bore 66 to the lower side of the flange 61. The pressure spring 64 has a pressure-force characteristic which will balance the control slide 54 in desired positions so that the desired maximum quantity of pressure medium to the hydraulic component is maintained independently of the pressure in the conduit 23a, so long as this exceeds a definite minimum pressure. The pressure spring 64 will try to hold the valve in the open position and the forces which balance the flanges 61, 56 so that the desired maximum quantity for the hydraulic component is: P] A p F wherein Pf designates the adjusted total spring pressure against the flange 61 and A p designates the pressure drop over the throttle arrangement 67 and F designates the end surface area of the slide, that is to say, the sum of the upper end area of the flange 56 and the upper annular area of the flange 61 outside the flange 57 or, in other words, the whole of the lower end surface area of the flange 61. On increasing the quantity on the feed side, the pressure drop A p increases and will cause the pressure spring to be pressed somewhat together and will move the slide correspondingly'so that the flow through the bores 51 becomes less until the fall in pressure which acts on the lower end surface area again is in equilibrium with the force of the spring and ensures a constant quantity of pressure medium through the valve 21a. The pressure in the feed conduit is regulated via the station by way of the regulatable safety valves 19a and 1%, by taking readings from the manometers 30 and 31.

7 According to the invention, the quantity control valve is regulated further with respect to the throughflowing quantity of medium without steps within the region from the maximum quantities of pressure medium for the hydraulic component and full stop, by remote control from the control panel 25 via a simple associated control valve 32 and a single associated conduit 36 between the quantity control valve 21 and the remote control valve 32.'A separate manometer 40 is inserted in the conduit 36.

The one'end of the conduit 36 is connected via a bore 68 in the cover 45 with the chamber 63 which forms the pressure control chamber of the remote control arrangement. The narrow bore 66 to the pressure control chamber 63 is substantially narrower than the bore 68 and the passage in the conduit 36, and the conduit 36 must be large enough to discharge a quantity of oil from the bore 66.

By means of a regulating screw 69 of the valve 32, one can, by rotation in opposite directions via a pressure spring 70a which acts on a valve portion 70, open and closea passage through the valve between the conduit 36 and a discharge conduit 71 to the discharge conduit 26 of the control panel and further to the tank 16. By utilising a definite stop limit for the regulating screw 69, the pressure spring can be adjusted to a definite maximum spring pressure, so that the valve 32 can serve as a maximum pressure valve.

In FIG. 2, the valve 32 is shown in the closed position. This involves the valve 21a acting as a conventional quantity control valve with the supply of the maximum'quantity of pressure medium to the hydraulic component. The pressure in the pressure control chamber 63 can be read off remotely at any time via the manometer 40 in the station.

By opening the valve 32 gradually, there is effected an increasing regulated tapping off of pressure medium from the pressure control chamber 63 so that independently of the pressure in the conduit 23a an intended gradually increasing pressure drop in the pressure control chamber 63 can be produced. This positively produced pressure drop in the chamber 63 causes the pressure spring 64 to be pressed together to a definite corresponding degree and the slide 54 correspondingly chokes off the amount of medium via the throttle flange 56 until the spring force of the pressure spring 64 again balances the fall in pressure which acts on the surface F. I

With a fully open valve' 32, the opening in the cross bore 51 is almost completely closed off by the throttle flange 56 so that one gets almost a full stop of the passage of medium in the quantity control valve and thereby a full stop of the supply of medium to the hydraulic component since provision is only made for a small flow via the conduit 36 to the tank 16.

So long as pressure is maintained on the feed side of the system one can keep a given hydraulic component or even combined hydraulic components disconnected by opening the associated remote control valve or valves. On starting up a hydraulic component, the remote control valve is completely. or partially closed and the quantity control valve is brought into a desired operating position all according to the-adjustment of the remote control valve.

If the pressure on the feed side of the systemfalls, the quantity control valve will automatically be placed in the open position by the pressure force of the spring 64'. With a new pressure build up on the feed side of the system, the combined quantity control valves which have open remote control. valves will be placed into position in a closed position, while the quantity control valves which have partially or fully closed remote control valves will gradually be adjusted tothe intended position gradually as the pressure builds up the individualquantity control valve. I

-By means of the manometer 40, the pressure in the conduit 36 can be read off at the remote control station and, if desired, the manometer can be calibrated so as to show the corresponding quantity of feed to the. hy-

draulic component.

In FIG. 3, there is shown a valve in which the quantity control valve is closed for passage to the hydraulic component when the remote control valve is open. The quantity control valve is constructed substantially the same as the quantity control valve of FIG. 2.'In addition, the outlet of the duct 42 is connected via a cylin drical bore 75 with an axially displaced dischargeduct 76 to the hydraulic component. In the bore 75, there is inserted a slide 77 with two flanges 78, 79. Between the flange 78 and the bottom of the bore 75, there is present a chamber 80 having a relatively weak pressure spring 81 and via the bottom of the bore there extends a duct 82 having a conduit connection to the discharge side of the system. Between the flange 79 and a bottom cover 83, there is formed a chamber 84 with a duct connection via a bore 85 and the bore 66 to the chamber63. Should there occur a sufficiently large drop in pressure in the chamber 63, that is to say on fully opening the valve 32, the pressure spring 81 moves the slide 77 in front of the discharge duct 76 and closes the passage to the hydraulic component. If the pressure in the system's feed side falls, the valve 21 is placed in-an open position as mentioned above and if the pressure is applied anew, there must first be built upsufficient pressure in the chamber 63 and the chamber 80 before the connection to the hydraulic component is again opened via the discharge duct 76.

What we claim is:

1. In a hydraulic system including at least two hydraulic components separately operable by means of predetermined mutually arbitrary quantities of pressure medium supplied from a common source of the latter via a common feed conduit through respective individually regulatable quantity control valves, each quantity control valve incorporating a throttle arrangement and a control slide which are adapted to establish the supply of a maximum quantity of pressure medium to their hydraulic component by balancing the pressure on the control slide in opposite axial directions, the control slidebeing in a first axial direction under a pressure load upstream of the throttle arrangement and in an opposite second axialdirection under a pressure load downstream of the throttle arrangement plus the pressure exerted by a pressure spring, and the control slide being provided with a throttle flange cooperable with a flow opening in a slide guide whereby the supply of pressure mediumto the region in front of the throttle arrangement is regulated depending upon the balance position of the control slide with increasing throttling by excess pressure in the first axial direction, the improvement consisting in the control slide in said second axial direction being under the pressure load downstream of the throttle arrangement plus the pressure exerted by said pressure spring'via a remotely controlled pressure control chamber which via a single conduit connection is connected, via a remote control valve, to a remotely disposed source of pressure discharge for separately regulating the balance position of the control slide and thereby regulating, as required, the actual quantity of pressure medium supplied to the hydraulic component.

' 2. The'system according to claim 1, wherein the sin- ,-gle conduit connection includes a manometer for re- -mote reading off of the pressure on the discharge side of the quantity control chamber.

3. The system according to claim 1, wherein the remote control valves each have a valve portion actuated valve via the pressure control by a pressure spring having a regulatable pressure force thereby forming a maximum pressure valve with a regulatable maximum pressure.

4. Thesystem according to claim 1, wherein there is formed between the discharge duct of the quantity con trol valveand the particular hydraulic .component a close valve passage which is controlled by a slide means the one side of which is loaded by pressure spring means and the opposite side'of which communicates via a passage with the pressure medium in the pressure control chamber of the quantity control valve.

5. In combination with a hydraulic system comprising at least two hydraulic components (22a, 22b), a common source of hydraulic fluid (10, ll a common feed conduit (20) connecting each said hydraulic component to said common source, and a plurality of quantity on o va ves 1a., 21;b)..ca omm talvsrbs n disposed between said common'feedconduit and a re: spective hydraulic componentvfor individually regulat- I ing a maximum quantity of flow of hydraulic fluid delivered-to said hydraulic component from said feed conduit,.each control valve including a control slide, a throttle arrangement and a pressure spring biasing said slide in an axial direction, said slide being biased under a first pressure load upstream thereof in said common feed conduit in opposition to said axial direction and being biased under a second pressure load downstream of said throttle arrangement in said axial direction; a

plurality of remote control means (32, 33) disposed at a common station (25), each remote control means being connected to a respective quantity control valve for tapping off a flow of hydraulic fluid from each respective quantity control valve downstream of said throttle arrangement to reduce said second pressure load to'individually reduce the flow of hydraulic fluid delivered .to said hydraulic component connected thereto.

6. The combination as set forth inclaim 5 wherein each said quantity control valve includes a control slide (54) slidablyv disposed between a feed duct (41) in communication with said common feed conduit and a discharge duct (42) in communication with a respective hydraulic component, a pressure control chamber (63) disposed axially on one side of said slide, a pressure spring (64) in said chamber biasing said slide in a direction to open said feed duct-(41) and a-bore (66) communicating said chamber with said discharge duct (43) to effect a common pressure therebetween, and wherein a respective remote control means is connected to said chamber to remove hydraulic fluid therefrom to reduce the force on said slide to effect at least a partial closing of said feed'duct (41).

7. The combination as set forth in claim 5 which further comprises a common discharge (16) connected in common to said hydraulic components and said remote control means to receive hydraulic fluid from said hydraulic components and said remote control means.

8. The combination as set forth in claim 7 wherein said common discharge is connected to said common source of hydraulic fluid to effect a closed-loop hydraulic system. a

9.'The combination-as set forth in claim 5 wherein each said remote control means includes an adjustable control valve (32) and a conduit (36) connecting-each ing at least two hydraulic components (22a, 225), a

common source of hydraulic fluid (l0, 1 l a common feed conduit (20) connecting each said hydraulic component to said common source, and a plurality of quantity control valves (21a, 2112), each control valve being disposed between said common feed conduit and a re spective hydraulic component for individually regulating a maximum quantity of flow of hydraulic fluid delivered to said hydraulic component from said feed conduit, each said quantity control valve including a control slide (54) slidably disposed between a' feed duct (41) in communication with said common feed conduit and a discharge duct (42) in communication with a respective hydraulic component, a pressure control chamber (63) disposed axially on one side of said slide, a pressure spring (64) in said chamber biasing said slide in a direction to: open said feed duct (41), a bore (66) communicating saidchambe'r with said discharg e'duct (43) to effect a common pressure therebetween, a bore connected to said discharge ductto receive hydraulic fluid, a second discharge duct (76) connected between said latter bore and a respective hydraulic component, a second slide (77) slidably mounted in said latter bore, a second chamber in said latter bore on one axial. side of said second slide, a discharge duct (82) communicating with said chamber with the exterior of said control valve, a third bore communicating said second chamber with said pressure control chamber (63) for effecting an equal pressure therebetween, and a second pressure spring (81) in said chamber biasing said second slide to close said second discharge duct in response to the pressure in said second chamber being reduced; a plurality of remote control means (32, 33) disposed at a common station (25), each remote control means being connected to said pressure control chamber 63) of a respective quantity control valve for tapping off a flow of hydraulic fluid from each respective quantity control valve to individually reduce the force on said slide to effect at least a partial closing of said feed duct to reduce the flow of hydraulic fluid delivered to said hydraulic component connected thereto. II I 

1. In a hydraulic system including at least two hydraulic components separately operable by means of predetermined mutually arbitrary quantities of pressure medium supplied from a common source of the latter via a common feed conduit through respective individually regulatable quantity control valves, each quantity control valve incorporating a throttle arrangement and a control slide which are adapted to establish the supply of a maximum quantity of pressure medium to their hydraulic component by balancing the pressure on the control slide in opposite axial directions, the control slide being in a first axial direction under a pressure load upstream of the throttle arrangement and in an opposite second axial direction under a pressure load downstream of the throttle arrangement plus the pressure exerted by a pressure spring, and the control slide being provided with a throttle flange cooperable with a flow opening in a slide guide whereby the supply of pressure medium to the region in front of the throttle arrangement is regulated depending upon the balance position of the control slide with increasing throttling by excess pressure in the first axial direction, the improvement consisting in the control slide in said second axial direction being under the pressure load downstream of the throttle arrangement plus the pressure exerted by said pressure spring via A remotely controlled pressure control chamber which via a single conduit connection is connected, via a remote control valve, to a remotely disposed source of pressure discharge for separately regulating the balance position of the control slide and thereby regulating, as required, the actual quantity of pressure medium supplied to the hydraulic component.
 2. The system according to claim 1, wherein the single conduit connection includes a manometer for remote reading off of the pressure on the discharge side of the quantity control valve via the pressure control chamber.
 3. The system according to claim 1, wherein the remote control valves each have a valve portion actuated by a pressure spring having a regulatable pressure force thereby forming a maximum pressure valve with a regulatable maximum pressure.
 4. The system according to claim 1, wherein there is formed between the discharge duct of the quantity control valve and the particular hydraulic component a close valve passage which is controlled by a slide means the one side of which is loaded by pressure spring means and the opposite side of which communicates via a passage with the pressure medium in the pressure control chamber of the quantity control valve.
 5. In combination with a hydraulic system comprising at least two hydraulic components (22a, 22b), a common source of hydraulic fluid (10, 11), a common feed conduit (20) connecting each said hydraulic component to said common source, and a plurality of quantity control valves (21a, 21b), each con-trol valve being disposed between said common feed conduit and a respective hydraulic component for individually regulating a maximum quantity of flow of hydraulic fluid delivered to said hydraulic component from said feed conduit, each control valve including a control slide, a throttle arrangement and a pressure spring biasing said slide in an axial direction, said slide being biased under a first pressure load upstream thereof in said common feed conduit in opposition to said axial direction and being biased under a second pressure load downstream of said throttle arrangement in said axial direction; a plurality of remote control means (32, 33) disposed at a common station (25), each remote control means being connected to a respective quantity control valve for tapping off a flow of hydraulic fluid from each respective quantity control valve downstream of said throttle arrangement to reduce said second pressure load to individually reduce the flow of hydraulic fluid delivered to said hydraulic component connected thereto.
 6. The combination as set forth in claim 5 wherein each said quantity control valve includes a control slide (54) slidably disposed between a feed duct (41) in communication with said common feed conduit and a discharge duct (42) in communication with a respective hydraulic component, a pressure control chamber (63) disposed axially on one side of said slide, a pressure spring (64) in said chamber biasing said slide in a direction to open said feed duct (41) and a bore (66) communicating said chamber with said discharge duct (43) to effect a common pressure therebetween, and wherein a respective remote control means is connected to said chamber to remove hydraulic fluid therefrom to reduce the force on said slide to effect at least a partial closing of said feed duct (41).
 7. The combination as set forth in claim 5 which further comprises a common discharge (16) connected in common to said hydraulic components and said remote control means to receive hydraulic fluid from said hydraulic components and said remote control means.
 8. The combination as set forth in claim 7 wherein said common discharge is connected to said common source of hydraulic fluid to effect a closed-loop hydraulic system.
 9. The combination as set forth in claim 5 wherein each said remote control means includes an adjustable control valve (32) and a conduit (36) connecting each remote control valve (32) to a respective quantity control valve.
 10. The combination as set forth in claim 9 wherein each said remote control means includes a manometer (4) in each said conduit thereof.
 11. In combination with a hydraulic system comprising at least two hydraulic components (22a, 22b), a common source of hydraulic fluid (10, 11), a common feed conduit (20) connecting each said hydraulic component to said common source, and a plurality of quantity control valves (21a, 21b), each control valve being disposed between said common feed conduit and a respective hydraulic component for individually regulating a maximum quantity of flow of hydraulic fluid delivered to said hydraulic component from said feed conduit, each said quantity control valve including a control slide (54) slidably disposed between a feed duct (41) in communication with said common feed conduit and a discharge duct (42) in communication with a respective hydraulic component, a pressure control chamber (63) disposed axially on one side of said slide, a pressure spring (64) in said chamber biasing said slide in a direction to open said feed duct (41), a bore (66) communicating said chamber with said discharge duct (43) to effect a common pressure therebetween, a bore (75) connected to said discharge duct to receive hydraulic fluid, a second discharge duct (76) connected between said latter bore and a respective hydraulic component, a second slide (77) slidably mounted in said latter bore, a second chamber in said latter bore on one axial side of said second slide, a discharge duct (82) communicating with said chamber with the exterior of said control valve, a third bore communicating said second chamber with said pressure control chamber (63) for effecting an equal pressure therebetween, and a second pressure spring (81) in said chamber biasing said second slide to close said second discharge duct in response to the pressure in said second chamber being reduced; a plurality of remote control means (32, 33) disposed at a common station (25), each remote control means being connected to said pressure control chamber (63) of a respective quantity control valve for tapping off a flow of hydraulic fluid from each respective quantity control valve to individually reduce the force on said slide to effect at least a partial closing of said feed duct to reduce the flow of hydraulic fluid delivered to said hydraulic component connected thereto. 